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The Best iPhone 6 Battery Case

Plenty of portable power in a slim, stylish two-piece design makes the Boostcase Power Case today’s best iPhone 6 battery case.

Boostcase Power Case

Even though iPhone battery life improves with every iteration, many users still find it nearly impossible to get through a full day without needing to recharge the battery. More than a few battery cases aim to fill that need. Consumers can choose from cases featuring a slim design, fun colors, price tags under $100, light weight, easy use — and of course, varying levels of charging capacity.

Among the many available options, the Boostcase Power Case ($99.95 on Amazon), the Tylt Energi Sliding Power Case ($99.99 on Amazon), the Incipio OffGRID Express ($79.99, $49.99 on Amazon) and the Otterbox Resurgence ($99.99, $79.61 on Amazon) rose to the top. They're all under $100, provide a full charge to your iPhone 6 and got high marks from both professional reviewers and consumers. I put these models through a week of testing to see which rose to the top. All performed well, but in the end the Boostcase emerged as the overall best battery case for the iPhone 6. Here's why.

Smart, user-friendly design

The Boostcase’s two-piece design allowed me to protect my phone in style while adding the battery sleeve only when I needed it—a big weight savings. I haven't liked this type of two-piece case in the past because they've been difficult to use, but I found attaching and detaching the Boostcase battery sleeve to be easy.

The snap-on design provides holes and grooves for the battery sleeve to snap onto. I thought it looked a little odd at first, but after noticing I could still see the gold color of my iPhone shining through the case, I found it quite attractive. When I wanted to add the battery, I placed the mounting dots into the grooves and slid it into place so that the lightning port fit securely into the connector.

When I was done charging, I slid the case back up and off.I found the Boostcase to be slim enough to fit into my pants pocket, even with the battery sleeve attached. The shell’s smooth, silky finish feels feels luxurious and provides a good grip on the phone.

The other two-piece option in my test group, the Tylt Energi Sliding case, uses a similar design, but points go to Boostcase for its more attractive inner case styling and its innovative battery status indicator. A simple tap on the battery sleeve illuminates the blue LED light running along the bottom of the case so I could see how much power was left or if I needed to charge the case before leaving home.

The case is easy take on and off. You can charge and sync your phone and the case at the same time. And there’s a toggle switch to turn the case on and off to preserve its charge.

This LED indicator is a nice improvement over the four or five blinking dots found on the other cases. To my eye, the bar gave me a quicker visual cue on whether I needed to top off. Unlike cases that make you press a button to light the dots, the Boostcase lights when you tap it

As an added bonus, only the Boostcase offers up fun colors like orchid, gold, clear, coral and black.

Compact, powerful battery

The Boostcase promises 100% more battery life for your iPhone from its 2700 mAH battery, offering a little less power than the Tylt Energi case (3200 mAh) and the Incipio OffGRID Express (3000mAh), and roughly on par with the OtterBox Resurgense's 2600 mAh battery. In my testing, I found all the cases capable of recharging my iPhone 6 to at least 90 percent, more than enough to get me through the day and back home or to the car to plug in.

Good access to ports

My one complaint with all these cases, not only the Boostcase Power Case, is that the added length at the bottom of the case makes it more difficult to plug in many types of headphones. Apple earbuds will work fine, but if you have headphones with a thicker or L-shaped connector, you will need a cord extender in order to reach the port. Each of these cases includes that extender except Tylt, which says you can request one from the company with proof of purchase.

Our pick last year for The Best iPhone 5 Battery Case, the Mili Power Spring 5 ($39.99 on Amazon), leaves the bottom completely open, providing easy access to both the headphone jack and the lightning port so I could charge the phone directly, if I wanted. Alas, it's not available in the U.S. for the iPhone 6, and it seems that other brands are moving in the direction of a covered bottom.

Another plus for the Boostcase is that it allows you to use the mute switch on your phone through an open slot, and you can see which position it’s in just by looking at it. I like to mute my phone when I'm on a call or in a meeting, so I use this switch a lot. Cases like the Resurgence, that cover the switch, make you toggle up or down to mute and unmute. I found it difficult not only to access the switch but also to know whether my phone was on mute or not.

Easy charging

Charging the Boostcase is simple. The micro-USB port is located on the bottom of the case for quick, easy access.

I had a much more difficult time charging the OtterBox Resurgence. Once I finally located the charging port on the side of the case, I broke a fingernail trying to open the flap that hides the port. The two-piece snap-together design makes it far more cumbersome.

The other cases were not as difficult to use, but I still found the Boostcase’s ease of use and access to ports to be the winner in this category.

The competition

The Tylt Energi Sliding Power Case proved to be a strong contender for best battery case, with a larger battery at the same price as the Boostcase. However, its somewhat bulkier form factor doesn't feel as comfortable to hold as the Boostcase, its inner sleeve for everyday use isn't as attractive and the case only comes in black. The Tylt also doesn’t include a headphone extender, like the other cases do. The battery level indicator on the back of the Tylt isn't as elegant and easy to see as the LED design on the bottom rim of the Boostcase.

If you really need impact protection for your phone, the OtterBox Resurgence may be the right case for you. It’s similar in price and battery capacity to the others but really excels with its trusted military-rated drop protection. There are drawbacks, though. All that protection creates a heavier case with more cumbersome access to ports and switches.

The Incipio offGrid Express Battery Backup Case for iPhone 6 wins on price at $79 and offers solid battery backup performance, but I wasn't a fan of its form factor which requires the battery sleeve to always be attached. The Incipio comes only in black and includes a headphone extender.

What others have to say

In PCMag's testing, the Boostcase's 2,700mAh battery performed nearly as well as the the Tylt Energi. "The 2,700mAh Boostcase added 4 hours, 5 minutes of streaming time. [And] to compare, the 3,200mAh Tylt Energi Sliding Power Case for iPhone 6 added 4 hours, 28 minutes in the same test.

While there were mixed reviews of the iPhone 5 version of the case, Boostcase has improved the quality of the charging connector to address consumer concerns. Currently, there aren't any stores with posted consumer reviews of the iPhone 6 version.

The bottom line

The Boostcase Power Case, with its attractive styling, wide variety of colors, flexible snap-on design and easy-to-access ports, wins my vote for the best iPhone 6 battery case. The case more than holds up to drops and bumps and lets you add battery-boosting power only when you need it. While some of its competitors may offer slightly more power, this doesn't offset the Boostcase's overall complete package of features.